Frequency-domain array technique analysis for the rupture duration time and geometrical characteristics of the 2001 Kunlun Mountain Pass earthquake     

张红霞  许力生  陈运泰  李春来  Klaus Stammler 《地震学报(英文版)》2008,21(1):11-23

In this paper, we briefly describe the principle of tracking energy radiation sources of large earthquakes using fre- quency-domain far-field array technique, present general steps of tracking energy radiation sources, and take the 2001 Kunlun Mountain Pass earthquake as an example to analyze key factors for setting parameters while pro- cessing data. Using broadband waveform data from a seismic array in Ethiopia and Kenya (EK Array), we obtain that the rupture initiation point of the 2001 Kunlun Mountain Pass earthquake is located in the east of Buka Daban Peak (35.92°N, 91.70°E), and the rupture duration time is less than 160 s, the rupture length about 520 km, with 180 km in the west of the initiation point and 340 km in the east, respectively. The western segment of the earth- quake fault bends towards southwest near Buka Daban Peak, which is in concordance with the surface rupture trace. The eastern segment apparently bends towards northeast near Xidatan, which is in agreement with the strike of Xidatan fault, but 30 km away from Xidatan fault. In addition, the results imply that the western segment of the earthquake fault appears erect while the eastern segment appears to be gradually dipping southwards.  相似文献   

基于多重测点数目标函数族的结构损伤识别方法     

张立涛  李兆霞  费庆国 《地震工程与工程振动》2008,28(6)

基于加速度时域测试数据进行结构损伤识别计算时,所用测试数据的点数必须足够多才能够使识别有效,但往往又容易出现收敛到局部极小解的情况。为解决这一问题,本文提出了基于多重测点数目标函数族的结构损伤识别方法;所谓多重测点数目标函数族,即由不同点数的测试数据出发构造一族目标函数,以取代传统的基于单一点数的目标函数;迭代计算时采用了：Tikhonov正则化技术以抑制解答的病态性。以Benchmark结构为算例,分析了两种基于单一点数的损伤识别计算难以收敛到正确解答的原因;并考证了文中提出的方法。计算结果表明：基于多重测点数目标函数族的结构损伤识别方法,使得识别计算易于收敛到正确解答;从而证明了本文提出的方法是有效的。  相似文献   

用频率域台阵技术推测2001年昆仑山口西大地震的破裂时间与几何特征          下载免费PDF全文

张红霞  许力生  陈运泰  李春来  K.Stammler 《地震学报》2008,30(1):12-25

概述频率域远场台阵技术应用于大地震能量辐射源的追踪原理,介绍利用这一技术追踪能量辐射源的一般步骤,并以2001年昆仑山口西大地震为例,分析资料处理中主要参数设置所需要考虑的关键因素. 通过分析埃塞俄比亚/肯尼亚地震台阵（EK台阵）的宽频带波形资料,获得了2001年昆仑山口西大地震的起始破裂点的位置,能量辐射源的空间分布特征,以及破裂持续时间. 根据EK台阵资料的分析结果,2001年昆仑山口西大地震的起始破裂点位于布喀达坂峰东侧（35.92deg;N,91.70deg;E）,破裂持续时间不超过160 s,破裂长度约520 km. 其中,初始破裂点以西为180 km,以东为340 km. 断层西段在布喀达坂峰附近向西南方向发生弯曲,与地表破裂吻合. 断层东段似乎在西大滩断裂附近向东北方向发生弯曲,其方向与西大滩断层的走向一致,但二者相距约30 km. 另外,分析结果似乎表明, 地震断层的西段近乎直立,而东段逐渐南倾.   相似文献   

Seismic site effects by an optimized 2D BE/FE method I. Theory, numerical optimization and application to topographical irregularities     

B. Gatmiri  C. Arson  K.V. Nguyen 《Soil Dynamics and Earthquake Engineering》2008,28(8):632-645

This paper deals with the evaluation of seismic site effects due to the local topographical and geotechnical characteristics. The amplification of surface motions is calculated by a numerical method combining finite elements in the near field and boundary elements in the far field (FEM/BEM). The numerical technique is improved by time truncation. In the first part of this article, the accuracy and the relevance of this optimized method are presented. Moreover, parametric studies are done on slopes, ridges and canyons to characterize topographical site effects. The second part deals with sedimentary valleys. The complexity of the combination of geometrical and sedimentary effects is underlined. Extensive parametrical studies are done to discriminate the topographical and geotechnical effects on seismic ground movement amplifications in two-dimensional irregular configurations. Characteristic coefficients are defined to predict the amplifications of horizontal displacements. The accuracy of this quantitative evaluation technique is tested and discussed.  相似文献   

Quantitative study on pollen-based reconstructions of vegetation history from central Canada     

《中国科学D辑(英文版)》2008,(8)

Based on high-resolution pollen records from lake cores in central Canada, the present study instructed pollen taxa assignations in ecosystem groups and modern analogue technique, reported major results of quantitative reconstructions of vegetation history during the last 1000 years, and discussed the validation of simulated vegetation. The results showed that in central America (115°-95°W, 40°-60°N), best analogue of the modern vegetation is 81% for boreal forest, 72% for parkland, and 94% for grassland-parkland, which are consistent with vegetation distributions of the North American Ecosystem II. Simulations of the past vegetation from the sedimentary pollen showed climate changes during the past 1000 years: it was warm and dry in the Medieval Warm period, cold and wet in the earlier period and cold and dry in the later period of the Little Ice Age. It became obviously increasing warm and drought in the 20th century. The present studies would provide us scientific basis to understand vegetation and climate changes during the last 1000 years in a characteristic region and in 10-100 year time scales.  相似文献   

Exploration of the extension of two lava tubes,faults and dikes using very low frequency-electromagnetic technique in NE Jordan     

Ahmad Al-Oufi  Hakam A. Mustafa  Eid Al-Tarazi  Jafar Abu Rajab 《Acta Geophysica》2008,56(2):466-484

The very low frequency-electromagnetic (VLF-EM) technique was used to delineate two sub-parallel lava tubes, faults and dikes in Umm El-Quttein area, NE Jordan. The investigation of the lava tubes was conducted through 22 VLF-EM profiles across lava strike; the length of profiles ranged from 700 to 1700 m. The lava tubes outcrop at two sites: Azzam cave and Al-Howa tunnel, characterized by slightly weathered basalt, columnar joints and fissure zones; qualitative interpretation of Fraser and Karous-Hjelt maps differentiate those zones as linear, elongated and circular anomalous zones. The 2-D tipper inversion of VLF-EM data and resistivity imaging had the potential to screen out three anomalous zones of likely resistivity contrast: the lava tube body with resistivity over 2500 Θ·m, the fractured zones with resistivity less than 500 Θ·m, and the host vesicular basalt with resistivity of 1500 Θ·m. The strike of lava tubes varied from SW to NE direction with depth less than 20 m and width from 10 to 30 m.  相似文献   

钻孔后压浆技术在苏通大桥基础工程中的应用   总被引：1，自引：0，他引：1  

布克明  殷坤龙  龚维明 《岩土力学》2008,29(6):1697-1700

钻孔灌注桩后压浆技术,使水泥浆液在高压下渗透、充填和挤密,与沉渣、泥皮、桩周和桩端土体发生物理化学固结,增大了土体和桩端的强度,改变了桩的受力类型,提高了桩侧摩阻力和端阻力,从而提高了单桩的承载力。在苏通大桥超长大直径桩中应用了桩底后压浆技术。通过试桩静载试验,决定在工程施工中采用U型压浆管方案。试桩结果表明,压浆后极限承载力测试值是压浆前的1.48～2.0倍,压浆后端阻力是压浆前的2.46～7.21倍,表明利用后压浆技术达到了节约工程投资、提高工程施工质量及可靠性的目的,并产生了较大的技术经济效益和良好的社会环境效益,这将促进我国公路桥梁建设的桩基技术迈向一个新台阶。  相似文献   

平衡剖面技术在地震资料解释中的应用   总被引：1，自引：0，他引：1  

周竹生  马翠莲  胡文武  孟葵 《煤田地质与勘探》2008,36(3):67-70

地震资料解释的正确与否直接关系到储层预测的结果与精度,所以平衡剖面解释作为一种辅助手段,对地震解释的多解性起到很好地制约效果,并为其定量化解释研究上开辟了道路。介绍了平衡剖面技术的基本原理和解释机理;以依奇克里油田阿依库木齐剖面为例,阐述了平衡剖面技术在地震解释中的应用效果。结果显示,该剖面构造复原效果较好。并针对平衡剖面技术在地震资料解释中的应用提出了需注意的问题。   相似文献   

国家庄煤矿8101工作面动水注浆堵水技术   总被引：3，自引：0，他引：3  

王则才 《煤田地质与勘探》2004,32(4):26-28

简要介绍了国家庄煤矿810 1工作面隐伏断层导致特大型奥灰水突出的经过,并分析了突水水源,还阐述了治理方案和堵水技术,为类似矿井的突水治理提供了经验。   相似文献   

复杂荷载条件下边坡稳定性的上限极限分析     

年廷凯  栾茂田  郑德凤  鲁志杰 《岩土力学》2006,27(Z2):264-268

基于极限分析上限定理与土的抗剪强度折减技术,考虑边坡顶面超载、坡体内孔隙水压力与地震惯性力等复杂荷载,建立了边坡稳定的极限平衡状态方程,采用优化方法求解边坡稳定安全系数及相应的潜在破坏模式。其中水与地震对边坡的影响作用通过虚功方程来体现,将孔隙水压力与地震惯性力当作外力荷载做功,将强度折减系数作为评价边坡稳定性的定量指标。通过典型算例的对比分析,验证了方法的合理性,并探讨了孔隙水压力、地震加速度系数对边坡稳定性的影响。  相似文献